Occurrence of blaNDM-7 within IncX3-type plasmid of Escherichia coli from India.
J Infect Chemother
; 23(4): 206-210, 2017 Apr.
Article
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| MEDLINE
| ID: mdl-28131738
ABSTRACT
BACKGROUND:
New-Delhi metallo-ß-lactamase-7 with higher hydrolytic activity than its ancestor NDM-1 is emerging across the globe including India. In this study, we have investigated the genetic context of blaNDM-7 and alteration in plasmid copy number under concentration gradient carbapenem stress. MATERIALS ANDMETHODS:
Six blaNDM-7 producing Escherichia coli isolates were obtained from Silchar Medical College and Hospital and the co-existence of other ß-lactamases and transferability of this resistant determinant was determined by transformation and conjugation assay followed by typing of the plasmid by PBRT method. Genetic context and plasmid stability of blaNDM-7 was also determined. The change in copy number of transconjugable plasmid carrying blaNDM-7 under exposure of different carbapenem antibiotics was determined by quantitative Real Time PCR.RESULTS:
All the six isolates carrying blaNDM-7 were conjugatively transferable through an IncX3-type plasmid and were also found to co-harbor blaCTX-M-15. Genetic analysis of blaNDM-7 showed an association of ISAba125, IS5 and a truncated portion of ISAba125 in the upstream region and bleMBL gene in the downstream region of blaNDM-7. Complete loss of the plasmids carrying blaNDM-7 was observed between 85th to 90th serial passages when antibiotic pressure was withdrawn. After analyzing the relative copy number it was observed that the copy number of the blaNDM-7 encoding plasmid was highly affected by the concentration of ertapenem.CONCLUSION:
The present study has first demonstrated presence of IncX3-type plasmid encoding blaNDM-7 within nosocomial isolates of E. coli. Measures must be taken to prevent or atleast slowdown the emergence of this resistance determinant in this country.Palabras clave
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Bases de datos:
MEDLINE
Asunto principal:
Plásmidos
/
Proteínas Bacterianas
/
Escherichia coli
Límite:
Humans
País/Región como asunto:
Asia
Idioma:
En
Revista:
J Infect Chemother
Asunto de la revista:
MICROBIOLOGIA
/
TERAPIA POR MEDICAMENTOS
Año:
2017
Tipo del documento:
Article
País de afiliación:
India